New to me Mariah 1993 diablo few ?'s

93diabloForme · 07-11-2012, 03:41 AM

Hello,
This is my first post so i guess its my introduction as well. I am buying a diablo next week put dep. on it on monday. Picked it up for 3500 interior in pretty decent shape few nicks here and there but is without major rips and tears. It has the 4.3 alpha in it.

I am pretty much new to boating. My family lived on a river growing up we always had boats but nothing nice usually small aluminums with crappy outboards that never ran worth of crap. My whole family has started into bigger boats the last couple years and we are all addicted. WHile the rest of my family still goes the outboard route, i have gone inboard as i can tinker on cars so this more closely matches.

Last year i bought a rough shape bayliner 89 i think with a 302 omc. I had it for a week and some gaskets let go in the carb and being short on money and having buyers remorse sold it pretty quickly for a little less than i paid for it. Ok lesson learned. I could have fixed it cheaply, but after buying i figured i didnt car for the half a(()_ed interior job or the bulky feeling of the over 3000lb boat.

Ok so thats some of my history, but onto the diablo. I wasnt going to buy this summer but couldnt pass this up. It will come with a 30 day warranty to allow me time to make sure everything is good.

First ? for you mariah guru's. What can i expect for speed out of the 4.3? He is saying he topped it out on gps at 32 mph. This seems horribly low. Keep in mind i would very rarely run over 40 but i bought the v6 for pulling my kids tubing and eventually other watersports. I still want the ability to run fast if i so choose. Is it even possible that someone changed the prop so drastically that it would only run 32? Should i assume there is something wrong? The guy seems to have good knowledge of boats small repair shop that also sells boats and cars.

Im also finding mixed information on the weight of the boat. Iboats.com says 1600 i assume with the 3.0 and nada says 2300 i think. 2 more cylinders doesnt equate to 700 lbs. Is there a place with the 93 brochures? that would also tell me top speed.

He had a flat spot in the starter so hes replacing that this week. Overall seems very good shape and the quality and fit and finish seem very nice on these boats. I will just start with that ? for now since this post has gone quite long.

Thanks in advance

Zackattack · 07-11-2012, 04:10 AM

Welcome aboard.

The 93 brochure boasts 50-52mph from the 4.3L and a couple more from the LX. So the 32 currently is under performing. But I think 45 ish is pretty realistic. The weight is 2200lbs. If you pull tubes and stuff though you are going to want to sacrifice a speed pitched prop for the hole shot prop(which may be whats on there).

Hope that helps a bit.

***ColoradoDiablo*** · 07-11-2012, 04:21 AM

Welcome to MOC!

What elevation are you at? Is your 4.3 a 2bbl or 4bbl carb? If you look at the prop it should have the size on the flange.
My Diablo runs 44mph at 5000ft with a Solas stainless steel 4 blade 17p prop. I did install a Edelbrock intake , Comp Cams roller rockers , and aluminum high performance exhaust manifolds.
Your boat should weigh in at about 23-2400lbs according to Mariahs Brochure. Top speed in optimum conditions should be 50-56mph depending on which engine(4.3 or 4.3LX)
You are going to love the boat! They handle great and ride nice.

Larry

***mikeyt*** · 07-11-2012, 01:09 PM

Welcome aboard. I wont make any negative comments about you buying a Bayliner cuz i think that speaks for itself.

Forget about the brochure's performance claims as they were trying to sell boats and boat speedos are always optimistic.

. Realistically, with everything running well and a standard 19" 3 blade prop (Larry has some elevation to deal with) you should be in the 45-47mph range and your WOT rpms should be at or very close to 4800. A top speed of only 32 (even on GPS) would indicate to me a serious problem somewhere.

Iboats weight claim of 1600lbs was likely for the outboard model that was made in 1993. The weight, with a few accessories stored on the boat and a full tank of fuel (23 US gals) will be right around 2500-2600lbs plus the weight of your trailer for pulling purposes so you will need a tow vehicle with at least a 3500lb tow rating.

Get it on the water & see how it performs!

93diabloForme · 07-11-2012, 01:57 PM

haha yeah The bayliner was well a bayliner. They are all over the place up here for cheap money, but i will say theres alot of mid to late 80's bayliners going strong up here. Not to say that makes them good or anything.

Elevation is around 400 ft

To be 100 percent honest I never even looked to see if it was a 2b or a 4b. I was just assuming a 2b which is ok for me. My paperwork for the boat doesnt say lx or not. I had read on here the gimbal bearing can cause lack of power/speed. thoughts?

It seems that if the prop had been changed it would be a drastic change wouldnt it? A lower end prop is good for what i want but didnt want it at wot to cruise at 30

voodoo · 07-14-2012, 02:29 PM

Quote:

Originally Posted by 93diabloForme

haha yeah The bayliner was well a bayliner. They are all over the place up here for cheap money, but i will say theres alot of mid to late 80's bayliners going strong up here. Not to say that makes them good or anything.

Elevation is around 400 ft

To be 100 percent honest I never even looked to see if it was a 2b or a 4b. I was just assuming a 2b which is ok for me. My paperwork for the boat doesnt say lx or not. I had read on here the gimbal bearing can cause lack of power/speed. thoughts?

It seems that if the prop had been changed it would be a drastic change wouldnt it? A lower end prop is good for what i want but didnt want it at wot to cruise at 30

Props can make a major difference.
I have 3 props, a 17p 4 blade for when the boat is maxed out at 9 persons, a 19p 4 blade for half load when I'm going to pull a tube and a 19p 3 blade stainless for when it's just a couple of us on a joy ride.
Top speed, hole shot and ride varies greatly with each setup.

93diabloForme · 07-14-2012, 03:24 PM

i spoke with the guy yesterday. He then said his top speed depended on water conditions. He said he had it to 38 on gps one other time. He also stated it was a 19 prop but im unsure if its 4 blade, but i do know it wasnt stainless. He assured me the gimbal bearing was fine. He then stated the motor is orininal and close to 20 years old and thats why it wouldnt push 45-50 mph. Thoughts?

***mikeyt*** · 07-14-2012, 03:40 PM

Quote:

Originally Posted by 93diabloForme

i spoke with the guy yesterday. He then said his top speed depended on water conditions. He said he had it to 38 on gps one other time. He also stated it was a 19 prop but im unsure if its 4 blade, but i do know it wasnt stainless. He assured me the gimbal bearing was fine. He then stated the motor is orininal and close to 20 years old and thats why it wouldnt push 45-50 mph. Thoughts?

Mine is 16 yrs old and it will push 48-50 and if its a 19" prop in good condition then it should be in the 45-47mph range given everything else in good condition. No prop change is gonna account for these kind of speed differences. If this thing only tops out at 32 or 38mph (depending on which story he's telling) then I think that you can assume that this is one tired motor....and its gonna cost you a bit of $$ to put it right.

voodoo · 07-14-2012, 08:06 PM

Quote:

Originally Posted by mikeyt

Mine is 16 yrs old and it will push 48-50 and if its a 19" prop in good condition then it should be in the 45-47mph range given everything else in good condition. No prop change is gonna account for these kind of speed differences. If this thing only tops out at 32 or 38mph (depending on which story he's telling) then I think that you can assume that this is one tired motor....and its gonna cost you a bit of $$ to put it right.

For sure..30 ish mph is not cool..
My 4000 lb Mariah (with a crappy painted hull) still does 50 ish mph in ideal conditions with a 5.7